The present invention relates to a system for attaching a pre-vaporizing bowl to the wall of a combustion chamber for a turbojet engine, more particularly such a system in which the pre-vaporizing bowl may be easily removed from the combustion chamber without subjecting the gas turbine engine to a machining operation.
A pre-vaporizing bowl is operatively disposed between a fuel injector and an upstream end wall of a gas turbine engine combustion chamber. The pre-vaporizing bowl mixes intake oxidizer, such as air, with the fuel injected through the fuel injector, this mixture subsequently passing into the combustion chamber where it is ignited.
A known system for attaching the pre-vaporizing bowl to the wall of combustion chamber is shown in U.S. Pat. No. 4,999,996 to Duchene et al. In this system, the pre-vaporizing bowl is permanently attached to the combustion chamber wall so as to enable relative generally radial movement between the pre-vaporizing bowl and the combustion chamber. Such relative movement occurs during the operation of the gas turbine engine due to the temperature differences between the combustion chamber and the remaining engine structure.
In the known system, a locating flange is fixedly attached to the pre-vaporizing bowl and has an extended, radial portion which passes through a slot defined by a support collar which is welded to the wall of the combustion chamber. A stop ring welded to the support collar restrains axial movement of the locating flange while permitting relative radial movement between the combustion chamber and the pre-vaporizing bowl.
By welding the various components together, this known system attaches the pre-vaporizing bowl to the combustion chamber such that it may not be readily removed from the combustion chamber. Consequently, any defect relating to either the combustion chamber or the pre-vaporizing bowl requires the assembly to undergo complex machining operations to remove the welds so that the pre-vaporizing bowl may be separated from the combustion chamber. Such work can only be carried out in a machine shop, which necessitates the complete disassembly of the gas turbine engine and the transportation of the combustion chamber/pre-vaporizing bowl assembly to a machine shop. Quite clearly, this increases the costs and time involved in repairing the combustion chamber/pre-vaporizing bowl assembly.